1. Field of the Invention
The invention relates to a method for packaging articles and/or objects and a device for carrying out said method.
2. Description of the Related Art
According to the prior art, articles or objects of the most different kinds are packaged with various packaging materials.
According to the prior art, articles or objects, including foods, are packaged with packaging materials which are formed elastically. On account of the packaging methods belonging to the prior art, the fields of application for these packaging methods, in which the articles or objects are packaged with elastically formed packaging materials, are very limited.
The packaging methods belonging to the prior art for a packaging of an article or object with a elastic packaging material are executed on the one hand with the aid of stretchers.
Hereby an expansion of the elastic packaging material is attained by means of the varying running speeds of rollers between which the elastic packaging material is guided. After the expanding of the packaging material, the article to be packaged is placed on or in the packaging material, and the elastic packaging material contracts through its restoring forces.
This method belonging to the prior art has the disadvantage that damage to the packaging material may occur through the expanding of the packaging material by means of the rollers.
The method belonging to the prior art is moreover very cost-intensive, as the mechanical expansion has to be executed very quickly on the one hand and high forces have to be generated for the expansion on the other.
Moreover, the packaging method belonging to the prior art has the disadvantage that it is hardly possible to pull the packaging material in its length and simultaneously in its width by means of the stretchers.
A further disadvantage of this method is that the expansion forces to be generated pull the elastic packaging material into a smooth, monoplane shape and thus a simultaneous shaping of the packaging material is not possible. For example, the packaging material formed as a monoplane foil becomes larger during expansion. It always remains, however, a monoplane foil and does not form a shape, for example a sleeve or the like.
A further disadvantage is that the force applied for expanding the elastic packaging material always acts on the packaging material only linearly at the contact points between the rollers. With this method, the entire force needed to expand the total surface of the packaging material is applied between two pairs of rollers at one point. This very often results in damage.
On the other hand, the prior art includes a packaging method (DE 39 08 585 C2) in which, for example, meat is packaged in elastic packaging material. This method belonging to the prior art provides for rods which are located parallel or approximately parallel or else conically to one another in a circle or approximately a circle. On the outside of the circle formed by the rods, the elastic packaging material is located In the form of a sleeve or bag. The meat is pushed through between the rods. For the expanding of the packaging material there are now two possibilities:
Either the packaging material is already placed in pre-expanded state on the rods, i.e. the packaging material is expanded by mechanical means which act on the rods, or the packaging product must induce an expansion of the elastic packaging material during the pushing through the rods by forcing the rods and the packaging material apart.
When pushing a joint of meat, for example, along the rods, the packaging material is pulled down by the rods. The packaging foil is applied to the meat with a pressure acting from all sides on the meat.
With this method it is indeed possible for the packaging foil to have a shape (sleeve shape).
However, this method belonging to the prior art has the disadvantage that the packaging method is not suitable for many products because the expansion of the rods and of the packaging material has to be induced by the product. One example to be given in this context is the packaging of diapers, as the diapers, due to their deformability, are not in a position to force the rods and the packaging material apart in a defined way. On being pushed through, the diapers are compressed by the confronted pressure instead of forcing the rods apart.
If the expanding of the packaging material is to be induced by the mechanical means acting on the rods, so that diapers, for instance, can be packaged, very complex mechanical constructions are necessary for this purpose.
A further disadvantage of this packaging method belonging to the prior art is that the expansion means used are always inside the packaging during the packaging procedure and can thus severely impede the packaging procedure.